1. Field of the Invention
The present invention relates to liquid crystal display devices, more specifically, to a liquid crystal display device used not only for small-size display but also for a large-size display panel such as a television.
2. Description of the Prior Art
A widely used active matrix liquid crystal display device includes thin film transistors (TFTs), picture element electrodes, and a counter electrode (a common electrode). Liquid crystal between the picture element electrode and the counter electrode is driven by applying a desired voltage between the picture element electrode and the counter electrode through a TFT. In this way, an image is displayed on a liquid crystal display panel.
A liquid crystal display device for color display further includes color filters of a plurality of colors on a substrate where the counter electrode is formed. Red, green, and blue filters are arranged so as to correspond to respective picture elements.
Each pixel region for color display is divided into three picture element regions. Moreover, the TFT and the picture element electrode are disposed in each of the three picture element regions, and a red, green or blue filter is disposed opposite to each picture element electrode. Three picture elements in red, green, and, blue collectively constitute one pixel.
Delta arrangement is adopted to some of small-size display devices and medium-size display devices as a mode of arranging three-color filters for pixels. However, in most liquid crystal display devices including ones used for televisions, red, green, and blue filters are aligned in the same direction in this order.
Liquid crystal display devices are growing in size and are now applied not only to computers but also to television display devices. However, although color liquid crystal display devices have been provided with higher resolutions as the size thereof have been increased, pixels of some color liquid crystal display devices particularly of those used for televisions are relatively large. Therefore, those used for televisions or the like are considered to have coarse color picture display.
A method of arranging color filters is disclosed in Japanese Patent Publication (KOKAI) 2000-98128 (hereinafter, referred to as Patent Reference 1). In the method, red, green, and blue rectangular patterns each in the same size are repeatedly arranged two by two in one pixel region surrounded by a black matrix.
However, TFTs as many as filter patterns are required when color filters are arranged in a conventional liquid crystal display device according to Patent Reference 1. In other words, along with the increase in the number of filters in a pixel region, there are also increases in the number not only of the TFTs but also of bus lines. In addition, the technique disclosed in Patent Reference 1 aims at reduction of unevenness at a boundary portion in photo composing which becomes necessary with upsizing. Though the technique may seem to be similar to the present invention at the first glance, it actually requires completely different techniques, designs, and configurations. Moreover, uneven shots may occur in shot boundary portions.
Coarseness of image display may be eliminated when a high-resolution liquid crystal display device is configured according to the prior art. However, the prior art cannot avoid problems such as reduction in yields, or price increases attributable to complex structures.